The invention relates to a device for forming stacks of flat products, comprising a first transportation section for transporting a stream of individual flat products of a first type, a second transportation section for forming an overlapping stream from the flat products of the first type, and a stacking unit for forming individual stacks from the overlapping stream.
The invention also relates to a method for forming stacks of flat products, comprising the following steps:                (a) generating a stream of individual flat products of a first type;        (b) transporting the stream of individual flat products of the first type;        (c) forming an overlapping stream from the individual flat products of the first type;        (d) forming individual stacks from the overlapping stream.        
In the production of flat products and, in particular, in the mass production of flat printing products, these flat products are generally individually transported away from a production machine and collated into an overlapping stream. This overlapping stream is then divided into stacks. These stacks are collected and for example banded or otherwise packed for onward dispatch.
Devices for carrying out this operation are also referred to as automatic delivery devices. Such devices are produced, for example, by the Assignee of the Applicants and are sold under the type designation delta700.
The stacks which are formed in this way, particularly when they are produced from limp flat products, exhibit the problem that they themselves are limp and often very rapidly fold over, which makes them difficult to handle and can result, moreover, in damage to the flat products.
It has further been shown that a simple banding of such a stack can result in the topmost and bottommost flat products possibly being damaged by external influences.
It has therefore proved advantageous to provide such stacks on the top and bottom side respectively with a flexurally rigid material, such as, for example, a firm piece of cardboard, in order, on the one hand, to lend the stack a certain rigidity and, on the other hand, to protect the topmost and bottommost flat products from damage.
It is also often desirable to provide a stack of flat products, either at the top or bottom, with a further flat product which offers, for example, more precise information on the content of the stack.
It is known to attach such further flat products to a stack by direct placement onto the stack.
This has the drawback, however, that it reduces the speed at which a stack-forming device is operated. Moreover, the overall size of the device specified in the introduction is also thereby markedly increased.